(1) Field of the Invention
The present invention relates generally to lifting devices, and more particularly to a device for lifting a torpedo nose in a horizontal orientation.
(2) Description of the Prior Art
It is often necessary in testing torpedoes to remove the nose section of the torpedo from the main body section. Removal and reconnection of the nose section requires alignment of the nose and body section. The torpedo is typically horizontally supported on a dolly during these operations. The main body section is cylindrical and can be readily supported in a horizontal fashion by the dolly. The nose section is hydrodynamically shaped (generally conical), requiring a specialized nose tilt dolly assembly to maintain the alignment of the nose section with the main body section. The torpedo is fully supported on a dolly assembly. When the nose section is unconnected from the main body, the nose tilt dolly is backed away from the main dolly to separate the nose section from the main body. The process is reversed to reassemble the torpedo. The nose tilt dolly assembly is very large and cannot be easily used in areas not specifically designed for torpedo refit, e.g., aboard a research vessel. A single point lifting device is needed in such areas where space is restricted. However, various configurations of components within the nose section may be tested. Each configuration may have a unique center of gravity, making it more difficult to maintain the nose section horizontally with a single point lift.
A number of hoist slings have been developed to support various shaped objects. U.S. Pat. No. 4,930,732 to Hardtke recites a yoke clip for lifting piping. The yoke pipe clip comprises a pair of generally parallel plates in a side-by-side spaced relationship which are placed transversely over the pipe, the plates having a lower edge contoured to fit the upper surface of the pipe. A pair of separator plates disposed one at each opposite end of the parallel plates maintains the separation between the parallel plates. A yoke is placed beneath the pipe, each of its free ends extending upward through one of the separator plates. A bolt is threaded onto the yoke ends and tightened against the separator plates, bringing the yoke and parallel plates to bear against opposite sides of the pipe. A suspension bracket is positioned between and interlocked with the parallel plates, and the pipe is lifted by this bracket. If the conical nose section were lifted with this yoke pipe clip, it would be canted from the necessary horizontal position.
U.S. Pat. No. 4,844,396 to Norton shows another mounting for attaching a sensor to a pipe, but which could be adapted for supporting a section of pipe. A bracket with flexible legs is placed over the pipe such that the legs extend slightly around the pipe. The bracket has vertical clips extending away from the top of the pipe. A chain is attached to and extends from one vertical clip, around the bottom of the pipe and is attached to the other vertical clip. Tightening the chain brings the bracket legs in firm contact with the pipe. The pipe can be lifted from the bracket, or a sensor can be mounted within the bracket such that the sensor is brought into contact with the pipe when the chain is tightened. As with the Hardtke device, no provision is made for maintaining a horizontal orientation when lifting a conical shape. U.S. Pat. No. 3,840,262 to Foster et al. provides a simple sling arrangement for lifting a pipe which also cannot easily be adapted to lift a conical section in a horizontal manner.